GAMS is a high-level modeling environment for mathematical optimization. GAMS can employ GLPK as its underlying solver by virtue of the COIN-OR GAMSlinks initiative. This feature relies on the COIN-OR Osi project, discussed here (with accompanying caveats).

GAMS and GLPK can also swap models at a low level using one of several common problem specification formats, including the MPS format. The GLPK interoperability page provides more information.